should i replace it with a new hard line. or just run a fuel hose instead and mount the hose to the chasie. from the tank to the engine.

 

I would recommend replacing the hard line with hard line. You can get it from a dealer and it is not that hard to replace if you can get the car on a hoist. If you only have a jack and jack stands you most likely won't be able to get enough clearance without dropping the entire rear end assembly out. I would replace both feed and return lines at the same time.

This is just my overly cautious, do it once and be done with it suggestion though.